I'm glad it worked for you.
In the sub, create a formula like this:
whilereadingrecords;
""
Insert a group on this formula and check
"repeat group header on each
page". Make sure this is your group #1. Then add
the header fields to this
new group header.
Since, as you discovered, subreports don't have page headers, creating a group on a 'blank' formula (so all records belong to this one group) and then checking 'repeat group header on each page', you are mimicing exactly what a page header does.